U.S. patent number 8,050,129 [Application Number 12/491,247] was granted by the patent office on 2011-11-01 for e-fuse apparatus for controlling reference voltage required for programming/reading e-fuse macro in an integrated circuit via switch device in the same integrated circuit.
This patent grant is currently assigned to Mediatek Inc.. Invention is credited to Chien-Chung Chen, Rei-Fu Huang, Che-Yuan Jao, Chia-Hsien Liu.
United States Patent |
8,050,129 |
Liu , et al. |
November 1, 2011 |
E-fuse apparatus for controlling reference voltage required for
programming/reading e-fuse macro in an integrated circuit via
switch device in the same integrated circuit
Abstract
An electrically programmable fuse (e-fuse) apparatus includes an
e-fuse macro and a switch device. The e-fuse macro is disposed in
an integrated circuit, and has a plurality of e-fuse units. The
switch device is disposed in the integrated circuit, and has an
output node coupled to the e-fuse units and a first input node
coupled to a first power source which supplies a first reference
voltage acting as a programming voltage of the e-fuse macro. The
switch device connects the first power source to the e-fuse units
when the e-fuse macro is operated under a programming mode.
Inventors: |
Liu; Chia-Hsien (Taichung,
TW), Huang; Rei-Fu (Hsinchu, TW), Chen;
Chien-Chung (Hsinchu, TW), Jao; Che-Yuan
(Hsinchu, TW) |
Assignee: |
Mediatek Inc. (Science-Based
Industrial Park, Hsin-Chu, TW)
|
Family
ID: |
32908792 |
Appl.
No.: |
12/491,247 |
Filed: |
June 25, 2009 |
Prior Publication Data
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Document
Identifier |
Publication Date |
|
US 20100328987 A1 |
Dec 30, 2010 |
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Current U.S.
Class: |
365/225.7;
365/226; 365/96; 365/227 |
Current CPC
Class: |
G11C
17/165 (20130101); G04B 19/065 (20130101); G04B
37/0481 (20130101); G11C 17/18 (20130101) |
Current International
Class: |
G11C
7/00 (20060101) |
Field of
Search: |
;365/96,225.7,226,227 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nguyen; VanThu
Attorney, Agent or Firm: Hsu; Winston Margo; Scott
Claims
What is claimed is:
1. An electrically programmable fuse (e-fuse) apparatus,
comprising: an e-fuse macro, disposed in an integrated circuit and
comprising a plurality of e-fuse units; and a switch device,
disposed in the integrated circuit and having an output node
coupled to the e-fuse units and a first input node coupled to a
first power source which supplies a first reference voltage acting
as a programming voltage of the e-fuse macro, wherein the switch
device connects the first power source to the e-fuse units when the
e-fuse macro is operated under a programming mode; the first power
source is inside the integrated circuit; the e-fuse macro has a
power connection node coupled to the output node of the switch
device and configured to receive the first reference voltage; when
the e-fuse macro is operated under the programming mode, the switch
device connects the first input node to the power connection node;
and when the e-fuse macro is operated under a read mode to output
stored bits, the switch device disconnects the first input node
from the power connection node to float the power connection node
such that no reference voltage external to the e-fuse macro is
supplied to the e-fuse macro via the power connection node.
2. An electrically programmable fuse (e-fuse) apparatus,
comprising: an e-fuse macro, disposed in an integrated circuit and
comprising a plurality of e-fuse units; and a switch device,
disposed in the integrated circuit and having an output node
coupled to the e-fuse units and a first input node coupled to a
first power source which supplies a first reference voltage acting
as a programming voltage of the e-fuse macro, wherein the switch
device connects the first power source to the e-fuse units when the
e-fuse macro is operated under a programming mode, wherein the
first power source is inside the integrated circuit; the switch
device further has a second input node coupled to a second power
source; the switch device connects the second power source to the
e-fuse units when the e-fuse macro is operated under a read mode;
and the second power source is inside the integrated circuit, and
supplies a second reference voltage different from the first
reference voltage.
3. The e-fuse apparatus of claim 2, wherein the e-fuse macro has a
power connection node coupled to the output node of the switch
device and configured to receive either the first reference voltage
or the second reference voltage; and the switch device comprises: a
first transmission gate, coupled between the first input node and
the power connection node, wherein the first transmission gate is
turned on when the e-fuse macro is operated under the programming
mode; and a second transmission gate, coupled between the second
input node and the power connection node, wherein the second
transmission gate is turned on when the e-fuse macro is operated
under the read mode.
4. The e-fuse apparatus of claim 2, wherein the e-fuse macro has a
power connection node coupled to the output node of the switch
device and configured to receive either the first reference voltage
or the second reference voltage; and the switch device comprises: a
first transistor, coupled between the first input node and the
power connection node, wherein the first transistor is turned on
when the e-fuse macro is operated under the programming mode; and a
second transistor, coupled between the second input node and the
power connection node, wherein the second transistor is turned on
when the e-fuse macro is operated under the read mode.
5. An electrically programmable fuse (e-fuse) apparatus,
comprising: an e-fuse macro, disposed in an integrated circuit and
comprising a plurality of e-fuse units; and a switch device,
disposed in the integrated circuit and having an output node
coupled to the e-fuse units and a first input node coupled to a
first power source which supplies a first reference voltage acting
as a programming voltage of the e-fuse macro, wherein the switch
device connects the first power source to the e-fuse units when the
e-fuse macro is operated under a programming mode, wherein the
first power source is inside the integrated circuit; the switch
device further has a second input node coupled to a second power
source; the switch device connects the second power source to the
e-fuse units when the e-fuse macro is operated under a read mode;
the second power source is external to the integrated circuit, and
supplies a second reference voltage different from the first
reference voltage; and the switch device is coupled to the second
power source via a specific pin of the integrated circuit.
6. The e-fuse apparatus of claim 5, wherein the e-fuse macro has a
power connection node coupled to the output node of the switch
device and configured to receive either the first reference voltage
or the second reference voltage; and the switch device comprises: a
first transmission gate, coupled between the first input node and
the power connection node, wherein the first transmission gate is
turned on when the e-fuse macro is operated under the programming
mode; and a second transmission gate, coupled between the second
input node and the power connection node, wherein the second
transmission gate is turned on when the e-fuse macro is operated
under the read mode.
7. The e-fuse apparatus of claim 5, wherein the e-fuse macro has a
power connection node coupled to the output node of the switch
device and configured to receive either the first reference voltage
or the second reference voltage; and the switch device comprises: a
first transistor, coupled between the first input node and the
power connection node, wherein the first transistor is turned on
when the e-fuse macro is operated under the programming mode; and a
second transistor, coupled between the second input node and the
power connection node, wherein the second transistor is turned on
when the e-fuse macro is operated under the read mode.
8. An electrically programmable fuse (e-fuse) apparatus,
comprising: an e-fuse macro, disposed in an integrated circuit and
comprising a plurality of e-fuse units; and a switch device,
disposed in the integrated circuit and having an output node
coupled to the e-fuse units and a first input node coupled to a
first power source which supplies a first reference voltage acting
as a programming voltage of the e-fuse macro, wherein the switch
device connects the first power source to the e-fuse units when the
e-fuse macro is operated under a programming mode, wherein the
first power source is external to the integrated circuit, and
supplies the first reference voltage; the switch device is coupled
to the first power source via a specific pin of the integrated
circuit; the e-fuse macro has a power connection node coupled to
the output node of the switch device and configured to receive the
first reference voltage; when the e-fuse macro is operated under
the programming mode, the switch device connects the first input
node to the power connection node; and when the e-fuse macro is
operated under a read mode, the switch device disconnects the first
input node from the power connection node to float the power
connection node such that no reference voltage external to the
e-fuse macro is supplied to the e-fuse macro via the power
connection node.
9. An electrically programmable fuse (e-fuse) apparatus,
comprising: an e-fuse macro, disposed in an integrated circuit and
comprising a plurality of e-fuse units; and a switch device,
disposed in the integrated circuit and having an output node
coupled to the e-fuse units and a first input node coupled to a
first power source which supplies a first reference voltage acting
as a programming voltage of the e-fuse macro, wherein the switch
device connects the first power source to the e-fuse units when the
e-fuse macro is operated under a programming mode, wherein the
first power source is external to the integrated circuit, and
supplies the first reference voltage; the switch device is coupled
to the first power source via a specific pin of the integrated
circuit; the switch device further has a second input node coupled
to a second power source; the switch device connects the second
power source to the e-fuse units when the e-fuse macro is operated
under a read mode; and the second power source is inside the
integrated circuit, and supplies a second reference voltage
different from the first reference voltage.
10. The e-fuse apparatus of claim 9, wherein the e-fuse macro has a
power connection node coupled to the output node of the switch
device and configured to receive either the first reference voltage
or the second reference voltage; and the switch device comprises: a
first transmission gate, coupled between the first input node and
the power connection node, wherein the first transmission gate is
turned on when the e-fuse macro is operated under the programming
mode; and a second transmission gate, coupled between the second
input node and the power connection node, wherein the second
transmission gate is turned on when the e-fuse macro is operated
under the read mode.
11. The e-fuse apparatus of claim 9, wherein the e-fuse macro has a
power connection node coupled to the output node of the switch
device and configured to receive either the first reference voltage
or the second reference voltage; and the switch device comprises: a
first transistor, coupled between the first input node and the
power connection node, wherein the first transistor is turned on
when the e-fuse macro is operated under the programming mode; and a
second transistor, coupled between the second input node and the
power connection node, wherein the second transistor is turned on
when the e-fuse macro is operated under the read mode.
12. An electrically programmable fuse (e-fuse) apparatus,
comprising: an e-fuse macro, disposed in an integrated circuit and
comprising a plurality of e-fuse units; and a switch device,
disposed in the integrated circuit and having an output node
coupled to the e-fuse units and a first input node coupled to a
first power source which supplies a first reference voltage acting
as a programming voltage of the e-fuse macro, wherein the switch
device connects the first power source to the e-fuse units when the
e-fuse macro is operated under a programming mode, wherein the
first power source is external to the integrated circuit, and
supplies the first reference voltage; the switch device is coupled
to the first power source via a specific pin of the integrated
circuit; the switch device further has a second input node coupled
to a second power source; the switch device connects the second
power source to the e-fuse units when the e-fuse macro is operated
under a read mode; the second power source is external to the
integrated circuit, and supplies a second reference voltage
different from the first reference voltage; and the switch device
is coupled to the second power source via another specific pin of
the integrated circuit.
13. The e-fuse apparatus of claim 12, wherein the e-fuse macro has
a power connection node coupled to the output node of the switch
device and configured to receive either the first reference voltage
or the second reference voltage; and the switch device comprises: a
first transmission gate, coupled between the first input node and
the power connection node, wherein the first transmission gate is
turned on when the e-fuse macro is operated under the programming
mode; and a second transmission gate, coupled between the second
input node and the power connection node, wherein the second
transmission gate is turned on when the e-fuse macro is operated
under the read mode.
14. The e-fuse apparatus of claim 12, wherein the e-fuse macro has
a power connection node coupled to the output node of the switch
device and configured to receive either the first reference voltage
or the second reference voltage; and the switch device comprises: a
first transistor, coupled between the first input node and the
power connection node, wherein the first transistor is turned on
when the e-fuse macro is operated under the programming mode; and a
second transistor, coupled between the second input node and the
power connection node, wherein the second transistor is turned on
when the e-fuse macro is operated under the read mode.
15. An electrically programmable fuse (e-fuse) apparatus,
comprising: an e-fuse macro, disposed in an integrated circuit and
comprising a plurality of e-fuse units; a switch device, disposed
in the integrated circuit and having an output node coupled to the
e-fuse units and a first input node coupled to a first power source
which supplies a first reference voltage acting as a programming
voltage of the e-fuse macro, wherein the switch device connects the
first power source to the e-fuse units when the e-fuse macro is
operated under a programming mode; and a protection unit, for
preventing the switch device from connecting the first power source
to the e-fuse units unless a password is inputted to the protection
circuit to unlock programming protection.
16. An electrically programmable fuse (e-fuse) apparatus,
comprising: an e-fuse macro, disposed in an integrated circuit and
comprising a plurality of e-fuse units; and a switch device,
disposed in the integrated circuit and having an output node
coupled to the e-fuse units and an input node coupled to a power
source which supplies a reference voltage, wherein the switch
device connects the power source to the e-fuse units when the
e-fuse macro is operated under a read mode to output stored bits,
the power source is external to the integrated circuit, and the
switch device is coupled to the power source via a specific pin of
the integrated circuit.
Description
BACKGROUND
The disclosed embodiments relate to one-time-programmable (OTP)
storage apparatuses, and more particularly, to electrically
programmable fuse (e-fuse) apparatuses which control a reference
voltage required for programming/reading an e-fuse macro in an
integrated circuit via a switch device implemented in the same
integrated circuit.
Electrically programmable fuse (e-fuse) apparatuses are
one-time-programmable (OTP) storage apparatuses widely used in
semiconductor devices to record customized data (e.g., a chip ID or
serial number) or repair defective elements inevitably remaining in
the integrated circuits due to the semiconductor process. As the
e-fuse apparatuses have become essential components to integrated
circuits, how to design the e-fuse apparatus therefore becomes an
important topic to circuit designers.
SUMMARY
In accordance with embodiments of the present invention, exemplary
e-fuse apparatuses each capable of controlling a reference voltage
required for programming/reading an e-fuse macro in an integrated
circuit via a switch device in the same integrated circuit are
proposed.
According to a first aspect of the present invention, an
electrically programmable fuse (e-fuse) apparatus is disclosed. The
e-fuse apparatus includes an e-fuse macro and a switch device. The
e-fuse macro is disposed in an integrated circuit, and has a
plurality of e-fuse units. The switch device is also disposed in
the integrated circuit, and has an output node coupled to the
e-fuse units and a first input node coupled to a first power source
which supplies a first reference voltage acting as a programming
voltage of the e-fuse macro. The switch device connects the first
power source to the e-fuse units when the e-fuse macro is operated
under a programming mode.
According to a second aspect of the present invention, another
electrically programmable fuse (e-fuse) apparatus is disclosed. The
e-fuse apparatus includes an e-fuse macro and a switch device. The
e-fuse macro is disposed in an integrated circuit, and has a
plurality of e-fuse units. The switch device is also disposed in
the integrated circuit, and has an output node coupled to the
e-fuse units and an input node coupled to a power source which
supplies a reference voltage. The switch device connects the power
source to the e-fuse units when the e-fuse macro is operated under
a read mode, the power source is external to the integrated
circuit, and the switch device is coupled to the power source via a
specific pin of the integrated circuit.
These and other objectives of the present invention will no doubt
become obvious to those of ordinary skill in the art after reading
the following detailed description of the preferred embodiment that
is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram illustrating a first exemplary implementation
of an e-fuse apparatus according to the present invention.
FIG. 2 is a diagram illustrating an exemplary embodiment of an
e-fuse macro shown in FIG. 1.
FIG. 3 shows a programming result of the e-fuse macro shown in FIG.
2.
FIG. 4 is a diagram illustrating a first exemplary embodiment of a
switch device shown in FIG. 1.
FIG. 5 is a diagram illustrating a second exemplary embodiment of
the switch device shown in FIG. 1.
FIG. 6 is a diagram illustrating a second exemplary implementation
of an e-fuse apparatus according to the present invention.
FIG. 7 is a diagram illustrating an exemplary embodiment of an
e-fuse macro shown in FIG. 6.
FIG. 8 is a diagram illustrating a third exemplary implementation
of an e-fuse apparatus according to the present invention.
FIG. 9 is a diagram illustrating a fourth exemplary implementation
of an e-fuse apparatus according to the present invention.
FIG. 10 is a diagram illustrating a fifth exemplary implementation
of an e-fuse apparatus according to the present invention.
FIG. 11 is a diagram illustrating a sixth exemplary implementation
of an e-fuse apparatus according to the present invention.
DETAILED DESCRIPTION
Certain terms are used throughout the description and following
claims to refer to particular components. As one skilled in the art
will appreciate, manufacturers may refer to a component by
different names. This document does not intend to distinguish
between components that differ in name but not function. In the
following description and in the claims, the terms "include" and
"comprise" are used in an open-ended fashion, and thus should be
interpreted to mean "include, but not limited to . . . ". Also, the
term "couple" is intended to mean either an indirect or direct
electrical connection. Accordingly, if one device is coupled to
another device, that connection may be through a direct electrical
connection, or through an indirect electrical connection via other
devices and connections.
In accordance with embodiments of the present invention, exemplary
e-fuse apparatuses each capable of controlling a reference voltage
required for programming/reading an e-fuse macro in an integrated
circuit via a switch device implemented in the same integrated
circuit are proposed. As the switch device used for control the
reference voltage fed into the e-fuse macro is disposed in the same
integrated circuit where the e-fuse macro is located, the e-fuse
apparatus can be controlled more easily, efficiently, and/or
accurately. For clarity, certain exemplary implementations of the
e-fuse apparatus are given as follows.
FIG. 1 is a diagram illustrating a first exemplary implementation
of an e-fuse apparatus according to the present invention. The
exemplary e-fuse apparatus 100 includes, but is not limited to, an
e-fuse macro 102, a switch device 104, an e-fuse controller 106, a
first power source 108, and a second power source 109. In this
exemplary embodiment, the e-fuse macro 102, the switch device 104,
the e-fuse controller 106, the first power source 108, and the
second power source 109 are all disposed in an integrated circuit
110. The first power source 108 supplies a first reference voltage
V1 acting as a programming voltage of the e-fuse macro 102, and the
second power source 109 supplies a second reference voltage V2
different from the first reference voltage V1. Specifically, the
first reference voltage V1 is required for programming the e-fuse
macro 102 under a programming mode, and the second reference
voltage V2 is required for reading the e-fuse macro 102 under a
read mode. With regard to the first power source 108 which supplies
the first reference voltage V1, it can be selected from the
existing internal power sources of the integrated circuit 110 to
meet the programming requirement.
FIG. 2 is a diagram illustrating an exemplary embodiment of the
e-fuse macro 102 shown in FIG. 1. Byway of example, not a
limitation, the e-fuse macro 102 includes a plurality of e-fuse
units 202, 204, and 206. It should be noted that only three e-fuse
units are shown in FIG. 2 for simplicity. Each of the e-fuse units
202, 204, and 206 includes a programmable fuse element 212, 214,
216 and a control element 222, 224, 226, where the control elements
222, 224, and 226 are simply implemented using metal-oxide
semiconductor (MOS) transistors. Before the e-fuse macro 102 is
programmed, none of the programmable fuse elements 212, 214, 216 is
blown. When the e-fuse macro 102 is operated under a programming
mode, a programming voltage (e.g., the first reference voltage V1
being 3.3V or 2.5V) will be fed into a power connection node NP of
the e-fuse macro 102. Each of the control elements 222, 224, and
226 is controlled by a corresponding control signal C.sub.0,
C.sub.1, C.sub.2 generated by the e-fuse controller 106 to
determine whether a corresponding programmable fuse element 212,
214, 216 should be blown. More specifically, each of the e-fuse
units 202, 204, and 206 stores "0" or "1" according to the
resistance state. For example, in a case where the e-fuse units
202, 204, and 206 are required to store "1", "0", and "1",
respectively, the control elements (e.g., NMOS transistors) 222 and
226 are turned on by the control signals C.sub.0 and C.sub.2, and
the control element (e.g., an NMOS transistor) 224 is turned off by
the control signals C.sub.1. Therefore, a large electrical current
resulted from the applied programming voltage at the power
connection node NP flows through each of the programmable fuse
element 212 and 216 due to the electrically conductive control
element 222, 226. As a result, the programmable fuse elements 212
and 216 are blown due to sufficient heat dissipation caused by the
large electrical current. The programming result of the e-fuse
macro 102 is shown in FIG. 3.
When the e-fuse macro 102 is operated under a read mode, the second
reference voltage V2 (e.g., 0V) will be supplied to the power
connection node NP of the e-fuse macro 102. As clearly shown in
FIG. 3, the e-fuse units 202 and 206 have high resistance, and the
e-fuse unit 204 has low resistance. Therefore, based on the instant
resistance state of each e-fuse unit, the data read from the e-fuse
macro 102 would include three bits "1", "0", and "1".
It should be noted that the aforementioned voltage levels of the
first reference voltage V1 and the second reference voltage V2 are
for illustrative purposes only. In an actual application, the
voltage levels of the first reference voltage V1 and the second
reference voltage V2 depend on the semiconductor process and the
operational condition.
As mentioned above, the power connection node NP of the e-fuse
macro 102 receives either the first reference voltage V1 or the
second reference voltage V2, depending upon the operational mode of
the e-fuse macro 102. In this exemplary embodiment, the delivery of
the first reference voltage V1 supplied to the power connection
node NP of the e-fuse macro 102 under the programming mode and the
second reference voltage V2 supplied to the power connection node
NP of the e-fuse macro 102 under the read mode are controlled by
the switch device 104 implemented in the integrated circuit 110. As
shown in FIG. 1, the switch device 104 has an output node NO
coupled to the e-fuse units 202, 204, 206 via the power connection
node NP, a first input node NI_1 coupled to the first power source
108 which supplies the first reference voltage V1, and a second
input node NI_2 coupled to the second power source 109 which
supplies the second reference voltage V2. The switch device 104 is
therefore implemented to connect the first power source 108 to the
e-fuse units 202, 204, 206 when the e-fuse macro 102 is operated
under the programming mode, and connect the second power source
108, instead of the first power source 108, to the e-fuse units
202, 204, 206 when the e-fuse macro 102 is operated under the read
mode.
FIG. 4 is a diagram illustrating a first exemplary embodiment of
the switch device 104 shown in FIG. 1. The exemplary switch device
104 includes a first transmission gate 402 controlled by control
signals WEN/ WEN generated by the e-fuse controller 106 and a
second transmission gate 404 controlled by control signals REN/ REN
generated by the e-fuse controller 106. The first transmission gate
402 is coupled between the first input node NI_1 and the output
node NO (which is further coupled to the power connection node NP),
where the first transmission gate 402 is turned on when the e-fuse
macro 102 is operated under the programming mode. The second
transmission gate 404 is coupled between the second input node NI_2
and the output node NO (which is further coupled to the power
connection node NP), where the second transmission gate 404 is
turned on when the e-fuse macro 102 is operated under the read
mode.
FIG. 5 is a diagram illustrating a second exemplary embodiment of
the switch device 104 shown in FIG. 1. The exemplary switch device
104 includes a first transistor (e.g., a PMOS transistor) 504
controlled by a control signal WEN generated by the e-fuse
controller 106 and a second transistor (e.g., an NMOS transistor)
504 controlled by a control signal REN generated by the e-fuse
controller 106. The first transistor 502 is coupled between the
first input node NI_1 and the output node NO (which is further
coupled to the power connection node NP), where the first
transistor 502 is turned on when the e-fuse macro 102 is operated
under the programming mode. The second transistor 504 is coupled
between the second input node NI_2 and the output node NO (which is
further coupled to the power connection node NP), where the second
transistor 504 is turned on when the e-fuse macro 102 is operated
under the read mode.
As shown in FIG. 1, the e-fuse controller 106 contains a protection
circuit 107 implemented for preventing the switch device 104 from
connecting the first power source 108 to the e-fuse units 202, 204,
206 of the e-fuse macro 102 unless a predetermined criterion is
met. In this exemplary implementation, the first input node NI_1
continuously receives the first reference voltage V1 (e.g., a high
voltage level) when the first power source 108 is a constant
voltage source which keeps outputting the first reference voltage
V1. If the switch device 104 is erroneously turned on due to
unexpected factors, the e-fuse units 202, 204, 206 of the e-fuse
macro 102 may be incorrectly blown to store erroneous data.
Therefore, the protection circuit 107 is implemented to guarantee
that the switch device 104 does not deliver the first reference
voltage V1 to the e-fuse macro 102 until the e-fuse macro 102 is
ready to be programmed. For example, before a correct 16-bit
password is inputted to the protection circuit 107 to unlock the
programming protection, the protection circuit 107 forces the first
transmission gate 402 to remain at an off status by properly
setting the control signals WEN/ WEN or forces the first transistor
502 to remain at an off status by properly setting the control
signal WEN. Please note that the protection circuit 107 is an
optional component, and may be omitted in other exemplary
embodiments of the present invention.
Regarding the exemplary implementation shown in FIG. 1, the second
reference voltage V2 (e.g., the ground voltage) has to be supplied
to the power connection node NP to correctly read out the data
stored in the e-fuse macro 102. However, if the e-fuse macro itself
can provide the reference voltage required under the read mode, no
additional external reference voltage is required to be supplied to
the e-fuse macro operated under the read mode. Please refer to FIG.
6, which is a diagram illustrating a second exemplary
implementation of an e-fuse apparatus according to the present
invention. The exemplary e-fuse apparatus 600 includes, but is not
limited to, an e-fuse macro 602, a switch device 604, an e-fuse
controller 606, and a power source 608. In this exemplary
embodiment, the e-fuse macro 602, the switch device 604, the e-fuse
controller 606, and the power source 608 are all disposed in an
integrated circuit 610. The power source 608 supplies a reference
voltage V1 acting as a programming voltage of the e-fuse macro 602.
Please note that no external reference voltage required under a
read mode is supplied to the power connection node NP of the e-fuse
macro 102. FIG. 7 is a diagram illustrating an exemplary embodiment
of the e-fuse macro 602 shown in FIG. 6. By way of example, not a
limitation, the e-fuse macro 602 includes aforementioned e-fuse
units 202, 204, and 206 shown in FIG. 3 and a MOS transistor 702
which offers electrostatic discharge (ESD) protection. The e-fuse
units 202, 204, and 206 are controlled by control signals C.sub.0,
C.sub.1, C.sub.2, respectively, and the MOS transistor 702 is
controlled by a control signal C.sub.3. When the e-fuse macro 602
is operated under a programming mode, a programming voltage (e.g.,
the reference voltage V1 being 3.3V or 2.5V) will be fed into the
power connection node NP of the e-fuse macro 602, and the control
signals C.sub.0, C.sub.1, C.sub.2 generated from the e-fuse
controller 606 decides what data should be recorded by the e-fuse
macro 602. When the e-fuse macro 602 is operated under a read mode,
the power connection node NP of the e-fuse macro 602 is floating,
and the MOS transistor 702 controlled by a control signal C.sub.3
is turned on to thereby provide the desired reference voltage V2
(e.g., a ground voltage) under the read mode.
As shown in FIG. 6, the switch device 604 has an output node NO
coupled to a power connection node NP of the e-fuse macro 602 and a
single input node NI coupled to the power source 608. In this
exemplary embodiment, the switch device 604 is therefore
implemented to connect the power source 608 to the e-fuse macro 602
when the e-fuse macro 602 is operated under the programming mode;
however, when the e-fuse macro 602 is operated under a read mode,
the switch device 604 disconnects the input node NI from the output
node NO to thereby float the power connection node NP. By way of
example, the switch device 604 can be simply implemented using one
transmission gate (e.g., the transmission gate 402 shown in FIG. 4)
controlled by control signals WEN/ WEN generated from the e-fuse
controller 606 or one MOS transistor (e.g., the PMOS transistor 502
shown in FIG. 5) controlled by a control signal WEN generated from
the e-fuse controller 606.
Similar to the exemplary embodiment shown in FIG. 1, the e-fuse
controller 606 in this exemplary embodiment shown in FIG. 6 also
include an optional protection circuit 607 to prevent the switch
device 604 from connecting the power source 608 to the e-fuse units
202, 204, 206 in the e-fuse macro 602 unless a predetermined
criterion is met. As the function and operation of the protection
circuit 607 are identical to that of the protection circuit 107,
further description is omitted here for brevity.
In the exemplary embodiment shown in FIG. 1, the first power source
108 and the second power source 109 are both disposed in the
integrated circuit 110; besides, in the exemplary embodiment shown
in FIG. 6, the power source 608 is disposed in the integrated
circuit 610. In this way, each of the integrated circuits 110, 610
does not need to reserve pin(s) for connecting external power
sources. The pin count can be reduced. In addition, as the switch
device 104, 604 is disposed in the integrated circuit 110, 610 for
controlling the internal reference voltage supplied to the e-fuse
macro 102, 602, no control circuit disposed outside of the
integrated circuit 110, 610 is required to control the delivery of
the reference voltage. Besides, the switch device 104, 604 in the
integrated circuit 110, 610 is verified and guaranteed to have the
capability of delivering the high electrical current needed to blow
one or more programmable fuse elements under the programming mode
as the e-fuse macro 102, 602 is formed in the same integrated
circuit 110, 610. However, regarding the use of a control circuit
which is disposed outside of the integrated circuit 110, 610 to
control the delivery of the reference voltage, the external control
circuit (e.g., an external switch device) may not meet the
requirement of delivering such a high electrical current needed to
blow one or more programmable fuse elements under the programming
mode. That is, if the external control circuit is not properly
selected, the programming failure of the e-fuse macro 102, 602 may
occur. Moreover, the programming of the e-fuse macro 102, 602 can
be done after the integrated circuit 110, 610 has been mounted on a
circuit board of a target application due to the switch device 104,
604 disposed in the same integrated circuit 110, 610 where the
e-fuse macro 102, 602 is located. Therefore, compared with
conventional programming means, the programming operation of the
e-fuse macro 102, 602 becomes easier and more efficient.
The exemplary embodiments shown in FIG. 1 and FIG. 6 are for
illustrative purposes only. Any alternative design having the
switch device disposed in an integrated circuit where the e-fuse
macro is located still obeys the spirit of the present invention.
For example, in other exemplary embodiments of the present
invention, the power source for supplying the reference voltage
required under the programming mode and/or the power source for
supplying the reference voltage required under the read mode can be
external to the integrated circuit where the e-fuse macro and the
switch device are located. These also fall within the scope of the
present invention. To put it simply, as long as the switch device
used for controlling the delivery of the reference voltage supplied
to the e-fuse macro is inside the integrated circuit, the e-fuse
apparatus still benefits from such an innovative design having an
internal switch device disposed in an integrated circuit
(chip).
FIG. 8 is a diagram illustrating a third exemplary implementation
of an e-fuse apparatus according to the present invention. The
exemplary e-fuse apparatus 800 shown in FIG. 8 is similar to the
exemplary e-fuse apparatus 100 shown in FIG. 1. The major
difference is that the first power source 808 which supplies the
first reference voltage V1 is external to the integrated circuit
810 where the switch device 104 is located. Therefore, the first
input node NI_1 of the switch device 104 is coupled to the first
power source 808 via a specific pin PI of the integrated circuit
810. In one implementation, the first power source 808 is a
constant voltage source which keeps outputting the first reference
voltage V1 when enabled. Therefore, the protection circuit 107 is
preferably implemented to provide the e-fuse macro 102 with
programming protection. As a person skilled in the art can readily
understand the function and operation of the components shown in
FIG. 8 after reading above paragraphs directed to the exemplary
embodiment shown in FIG. 1, further description is omitted for
brevity.
FIG. 9 is a diagram illustrating a fourth exemplary implementation
of an e-fuse apparatus according to the present invention. The
exemplary e-fuse apparatus 900 shown in FIG. 9 is similar to the
exemplary e-fuse apparatus 100 shown in FIG. 1. The major
difference is that the second power source 909 which supplies the
second reference voltage V2 is external to the integrated circuit
910 where the switch device 104 is located. Therefore, the second
input node NI_2 of the switch device 104 is coupled to the second
power source 909 via a specific pin PI of the integrated circuit
910. In one implementation, the internal first power source 108 is
a constant voltage source which keeps outputting the first
reference voltage V1 when enabled. Therefore, the protection
circuit 107 is preferably implemented to provide the e-fuse macro
102 with proper programming protection. As a person skilled in the
art can readily understand the function and operation of the
components shown in FIG. 9 after reading above paragraphs directed
to the exemplary embodiment shown in FIG. 1, further description is
omitted for brevity.
FIG. 10 is a diagram illustrating a fifth exemplary implementation
of an e-fuse apparatus according to the present invention. The
exemplary e-fuse apparatus 1000 shown in FIG. 10 is similar to the
exemplary e-fuse apparatus 100 shown in FIG. 1. The major
difference is that the first power source 1008 which supplies the
first reference voltage V1 and the second power source 1009 which
supplies the second reference voltage V2 are both external to the
integrated circuit 1010 where the switch device 104 is located. In
this exemplary embodiment, the first input node NI_1 of the switch
device 104 is coupled to the first power source 1008 via a first
specific pin PI_1 of the integrated circuit 1010, and the second
input node NI_2 of the switch device 104 is coupled to the second
power source 1009 via a second specific pin PI_2 of the integrated
circuit 1010. In one implementation, the first power source 1008 is
a constant voltage source which keeps outputting the first
reference voltage V1 when enabled. Therefore, the protection
circuit 107 is preferably implemented to provide the e-fuse macro
102 with proper programming protection. As the function and
operation of other components shown in FIG. 10 are described in
above paragraphs directed to the exemplary embodiment shown in FIG.
1, further description is omitted for brevity.
FIG. 11 is a diagram illustrating a sixth exemplary implementation
of an e-fuse apparatus according to the present invention. The
exemplary e-fuse apparatus 1100 shown in FIG. 11 is similar to the
exemplary e-fuse apparatus 600 shown in FIG. 6. The major
difference is that the power source 1108 which supplies the
reference voltage V1 is external to the integrated circuit 1110
where the switch device 604 is located. Therefore, the input node
NI of the switch device 604 is coupled to the power source 1108 via
a specific pin PI of the integrated circuit 1110. In one
implementation, the power source 1108 is a constant voltage source
which keeps outputting the reference voltage V1 when enabled.
Therefore, the protection circuit 607 is preferably implemented to
provide the e-fuse macro 602 with proper programming protection. As
a person skilled in the art can readily understand the function and
operation of the components shown in FIG. 11 after reading above
paragraphs directed to the exemplary embodiment shown in FIG. 6,
further description is omitted for brevity.
Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention.
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